Device for mechanically recording sound in two tracks



ACKS' K. DE BOER May 4, 1 94s.

DEVICE FOR MECHANICALLY RECORDING SOUND IN TWO TR Filed Jan. 29, 1943 INVENTOR Kan/van a: 50:7? %K%M ATTORNEY Patented May 4, 1948 DEVICE FOR MECHANICALLY RECORDING SOUND IN TWO TRACKS Kornelis De Boer, Eindhoven', signor to Hartford National Netherlands, as- Bank and Trust Company, Hartford, Conn, as trustee Application January 29,

In the Netherland 1943, Serial No. 474,000 March 29, 1941 Section 1, Public Law 690, August s, 1946 Patent expires March 29, 1961 3 Claims.

Devices for mechanically recording sound in several, for example two, tracks on a band-shaped carrier are known. These recording devices comprise two rotary drums on which the film travels and on which the recording takes place. In this case corresponding points of the sound tracks are consequently displaced over some distance in the longitudinal direction of the film. In the reproduction this distance must be taken into account in order to obtain synchronous reproduction of corresponding parts of the various sound tracks.

The drawback of this method is, however, that there must be provided various spatially separated reproducing devices so that the reproducing equipment considerably increases in size. Moreover, themutual distance of corresponding points often varies in the lapse of timebetween the recording and the reproduction due to elongation or shrinking of the film so that synchrony between the sound tracks is not alawys ensured.

In photographically recording sound in a plurality of tracks it is known to record corresponding points of the sound tracks side by side so that the above-mentioned drawbacks are avoided. In mechanical recording it has hitherto been impossible for constructional reasons to place the two recording needles side by side within the available track width.

According to the invention, these drawbacks are eliminated by constructing at least one of the phonogram recorders in such manner that it may be present between the recording drum and the base plate of the apparatus so that the two recorders may be placed on either side of the recording drum, in such manner that the record-.- ing needles of these recorders are located side by side on the circumference of the recording drum. In order to be able to record the two sound tracks exactly side by side on the carrier, it is furthermore necessary that the two phonogram recorders are secured by the same means of support to a common base plate and that the shaft of the recording roller is likewise supported by this base plate.

If all the above-mentioned requirements are satisfied, it is possible to record two sound tracks in a reliable manner side by side at the same point on a carrier in such manner that the reproducing devices maybe united toiform one constructional unit and need not be adjustable with respect to one another. The phonogram recorder present between the drum and the base plate of the apparatus should have the smallest possible height in order to avoid unnecessary lengthening of the shaft of the recording drum and thus bending and vibrations in this shaft.

The invention will be explained more fully with reference to one embodiment thereofJ.

Fig. 1 represents a lateral elevation of a mechanical recording device for two sound tracks located side by side and Fig. 2 represents a front-view of this device. In the figures I0 denotes a base plate having mounted on it all the components essential for mechanical recording. This plate in has rigidly secured in it a pin H which passes through and fits exactly in a hole provided in each of. the phonogram recorders i3 and i4. With the aid of a cap nut l2 the two phonogram recorders are held firmly on the pin II so that any undesired displacement of the recorders 'relatively to one another and to the base plate in is excluded. In the same base plate is journalled, through the intermediary of a bronze bush H, the shaft I6 of a recording drum IS. The two recorders I3 and I 4 are arranged on either side of this drum in such manner that chisels I 8 and i9 respectively of these recorders are located side by side opposite the circumference of the drum. With the aid of a known construction of guide rollers and pressure rollers and carrier 30 in which the two sound tracks are to be recorded is caused to travel along the circumference of the drum i5 underneath the chisels l8 and I9.

In order to render possible the above-men,- tioned arrangement on either side of the record ing drum with the chisels side by side on the circumference of the drum, the chisel must be directed in the one recorder in a sense opposite to that of the other recorder, reckoning with respect to the means of attachment of the recorder, in the present instance the hole'for the pin Ii and adjusting lugs 23 and 2 4 which will be described hereinafter. Moreover, one of the two recorders is present between the recording drum l5 and the base plate [0. Since, in view of vibrations and bending under the pressure of the cutting chisels l8 and IS, the length of the shaft 1 6 must be kept as small as possible, the recorder I 4 has been given a very fiat shape. A permanent magnet 2!, which is commonly placed against the side-faces of the pole shoes is arranged for compactness on that side of the. re-

der to be able to compensate for small tiivergencies due to the use of different chisels, at least one of the recorders must bere-adjustabl'ehi-the direction of travel of the carrier, i. e. 1-ini the- 'direction of the line tangent to the roller at the point of recording. This is -achievd byi providing in the recorder IS a sleeve zz through which the supporting pin ll passes eccentrically.

drum member, another phonogram recording member arranged on the opposite side of. said drum member and having the recording element thereof positioned over the circumference of said drum member adjacent to the recording element of the first of said recording members, and means tosupport' said'recording' members "on said base plate. 7

2. A device for mechanically recording sound in two sound tracks on a band-shaped carrier,

1xinmprising--=a -l::ase'*plate member, a recording ii'r' um iniember having its axis substantially perpendicular to the base plate and spaced thererom,' f'a'rotatabie shaft for said drum member journalled"' 'in""said base plate, a phonogram recording'mer'hber arranged between the base iiplateiandithersaid drum member and having the recfirdl'rig 'element thereof positioned over the circumference of said drum member, another By turning the sleeve 22, for exaniple with the ...plionogra;ni" 're'cording member arranged on the aid of a micrometer screw, it is possible to readjust the chisel !9 relatively to the chisH-S.

The cutting depth of each of the chisels l8 and "lG-may also be re-adjustedseparately. On-the baklpart each recorder is provided with a lug; 23 and 24-respectively, -the length of which can-be adjusted for each' recorder :sep'arately with the aid of-a m'icrometer screw which is not shown. Under the--action of a heavy :spring, *which: isnot shown in the drawing',these lugs :23 and '-2-4= are drawn against the outer' surface-of an eccentrically supported roller =26. Theshaft 25 of-"this roller is secured in the base plate l0. 0wi-ngto the-ID1721710171. of "the roller 26 the chisels l 8 and 1'9 :are simultaneously brought intoand out of 'cohtact'=with-the carrier on' the drum '15. -The e iiact adjus'tment of 'each separate chisel'is'regiilated by re -adjusting the lugs 23"and '24 respectively.

nllthough in the "foregoing a "chisel: :has been described as the" mechanically recording tool, it is ev-ident that the invent-ion may-be iappli-edmo any 'method of recording wherein two tracks have to be r'ecorded side by side -on a single carrier with'Tthe aidof needles, sapphires; chisels or otli'errmechanically operating tools. --The-inventionrmay therefore "also be :applied to a a": method whereinj-"w'ith" the *aidof two' chis'els having! bevel cutting edges which "form tog'ether "a "V,--two unilaterally modulated 'Ioptically reproducibie tracks are "cut in a; carrier "comprising! an Iopa'que th top' iayenand a' tra'nsparent recording layer,

is snown' in Figta.

i f *n :recording use ls madezci azmethed l'r nown in itself -idr varying the avi ge ciitting 5 td 'tlie baseplate'andspacedtherefrom;a rotatable 'sha'ftfor- 'said' drum member j'ournaile nzrsaid base'iplate, a phondgram recording .rneinberarranged between the basepiate and thesaid drum member and having the reeording element thereof 'positioned over the circumierenceiof said opposite "side of said drum member and having theilr eicbiding element thereof positioned over the circumference of said drum member adjacent to the recording' 'element'of the first of -.said record- 5 ing smem'bers; meansto su-pp'ort-'rsaid-recording members 'on saidebase ..pl:'ate comprising-a pin :member-s'ecured to :said= basetplate andrj ournalled through saidfrecordi-ngsmembersga member-com- :inoncto the 'recording membersm'to:simultaneously 30 rotate the=same= aboutithesaid pimmember as' a :pivot fora-placing Ethewsaid:rrecbrdingelements -into=operative position, and-.-adjustable:stopmemberscenga'gingthe=rsaid recordingkamember and the :said- "member --'common-% Fto' both recording members for independently rotating one oil-said 'rec'ordingvmembersabout:saidapiri-member.

3.':A :-deviceflora-mechanicallyrecording sound in two-sound tra'ckss on a band shapedwcarrier,

comprising-L a base platehmemben a recording journal-led i said c baseri plate; ea :phonogram recordingfrmemben arranged met/ween ithe'-:base

p1931163211211iti iifiam mmmmbl ianda avlingithe recording 'element :Ithereof iipositioned over "the eireumrerence fidffi saidi rdi'tumzsmember, another .phonngram recordingmembersarranged n the 0 oppositeiside loffisaicriimmimiember a'ndihaving the recordmgselenientithereofipositioned over: the ieircumfereneeiof saidinrumimemberzadiacentrto the recording element of theii'irstioffisaid reeording-l menibers,:lmeansitorsuppor ssai'd'i ecording members on sairl"baseipl ate iba's reeordingielement's, 'saidimeans comprising arotat-able sleeve' -member having eccentricallyre- =lated inrierand mter surfa'ces and' positioriing me sa s- 1 reccmmg members on the pm member. p

v V nrs DEFBOER.

REN GES CPPED i lihelf-ollowingPreferences are-of \record in the file of this patent: e r

FQREIGN PATENTS Number Co'untry fDate b18353 IGi'at Bfitain 19043 2632131 "-lGreatBritain Mar."l2,"1928 

